Expression analysis of mir-21 and mir-221 in cancerous tissues from Iranian patients with gastric cancer

Early detection is a key to survival for gastric cancer. Molecular markers such as miRNA [microRNA] can have great importance in the early diagnosis of gastric cancer. Expression of miR-21 and miR-221 are deregulated in many types of human cancers. This study aimed to investigate the differences in miRNA expression patterns within the Iranian population. Total RNA was extracted from gastric cancer tissues and adjacent non-cancerous tissues from 32 patients. Expression levels of miR-21 and miR-221 were detected by Real time RT-PCR using a specific primer, with 5s rRNA as the internal reference gene. Our data showed that the expression levels of miR-21 and miR-221 in gastric cancer samples were significantly higher than in paired non-cancerous samples [P < 0.05]. The receiver operating characteristic [ROC] analyses yielded the area under the curve [AUC] values of 80.30 for miR-21 and 93.30 for miR-221, and combined ROC analysis revealed the highest AUC value of 96.90 in discriminating GC patients from healthy controls. It seems that miR-21 and miR-221 expression pattern in Iranian patients with gastric cancer are similar to any other population. Considering the increased expression level of two miRNAs in cancerous tissue compared to normal tissue as well as the area under ROC curve, miR-21 and miR-221 can be used for early detection of gastric cancer

Improved real-time RT-PCR assays of two colorectal cancer peripheral blood mRNA biomarkers: a pilot study

Background: efficient screening for detection of colorectal cancer [CRC] at earlier stages reduces its mortality. The purpose of this study was to investigate expression of carcinoembryonic antigen [CEA] and human telomerase reverse transcriptase [hTERT] mRNA in peripheral blood of CRC patients and to present strategies for early detection screen test

Methods: twenty seven patients in non-metastatic stage and 27 healthy individuals were studied. Expression of CEA, hTERT mRNA and 18srRNA [18s subunit of ribosomal RNA, as reference gene] were determined based on real-time RT-PCR on 3 [micro]g of total RNA from blood in 3 separate vials [1 [micro]g per vial]

Results: positive expression rate of CEA mRNA [78%] and hTERT mRNA [81%] were higher in patient group [P<0.001]. These rates were meaningfully higher than the results of individual vials containing only 1 [micro]g of total RNA. Difference between Ct values of markers with 18srRNA [[DELTA]Ct] was higher in healthy group than patient one. Therefore, a [DELTA]Ct cut-off value was determined for distinguishing between true- and false-positive results. Concurrent expression of both markers was found in 67% of the patients, which was higher than healthy cases [11%]. Combination of concurrent marker expression with cut-off point strategy increased specificity to 100%

Conclusion: these results showed that concurrent evaluation of marker expression and performing the test on 3 [micro]g of samples in 3 separate vials may increase specificity and sensitivity of real-time RT-PCR for early detection of non-metastatic CRC. However, more investigations with larger numbers of samples are needed to verify these results. Iran. Biomed. J. 17 [1]: 15-21, 2013